Multinuclear magnetic resonance studies. Part 2. Diphosphanes and dithioxodi-λ⁵-phosphanes

Abstract

Carton-13 and phosphorus-31 n.rn.r. spectra have been obtained for a number of tetra-alkyldiphosphanes and tetra-alkyldithioxodi-λ5-phosphanes of general formulae (R1R2P)2 and [R1R2(S)]2 respectively. Some analogous compounds with phenyl substituents have also been studied. Satellite resonances in 31P resonance due to W.-containing isotopomers have been examined. The data are treated, together with 1H n.m.r. studies where appropriate, to obtain (P,P) and (P,C) coupling constants, as well as 13C and 31P chemical shifts. These n.m.r. parameters are discussed in terms of steric interactions and stereoisomerism. The values of |1Jpp| for both series of compounds increase markedly as the size of the substituents increases. and this effect correlates with an increase in δp.